This invention relates to a technique for restoring cross-connection information in a digital cross-connect system.
Most present-day telecommunications networks typically include one or more Digital Cross-Connect Systems (DCSs) for electronically cross-connecting various incoming trunks to selected outgoing trunks in much the same way as a telecommunications switching system. With a DCS, the connections are set up in advance of the call, and typically remain in place thereafter until such time as a technician alters such connections to de-provision old service and/or provision new service. In some instances, the DCS connections become lost when the DCS becomes inoperative due to a disaster, such as a fire, flood, earthquake, or explosion. Moreover, during certain types of maintenance operations, a telecommunications service provider may purposely remove a DCS from service, causing a loss of such connections. Restoration of service requires that the cross-connections be restored, either by restoration of DCS itself, or by replicating the cross-connections on another DCS.
Restoration of the DCS cross-connections is usually a time-consuming operation. In case of a disaster, spare DCS capacity may no longer exist on site. Under such circumstances, one or more restoration DCSs must be transported to the disaster site. Thereafter, technicians must replicate the cross-connections on the restorations DCSs. U.S. Pat. No. 5,420,917, xe2x80x9cAutomated Recovery of Telecommunications Network Elementsxe2x80x9d, issued on May 30, 1995, in the name of Richard Guzman, and assigned to ATandT Corp., the assignee of the present invention, describes a method for automated restoration of one or more inoperative DCSs in a telecommunications network. In accordance with the teachings of the ""917 patent (herein incorporated by reference), restoration of one or more inoperative DCSs is accomplished by first connecting the restoration DCSs through guided media, in the form of cables, radio channels or the like, to the inoperative DCSs. Thereafter, the profile of each inoperative DCS (i.e., its cross-connection data) is obtained from a network database, referred to as the DCS Operation Support System (DCS-OSS) that stores circuit orders (cross-connect data) in a state database (SDB). A technician then translates the cross-connections needed to restore the each inoperative DCS into a circuit map in accordance with the cross-connect capability of each restoration DCS. The circuit map is ported to the restoration DCSs and is thereafter executed by such DCSs to restore service.
While the restoration technique disclosed in the ""917 patent is effective, the technique nevertheless suffers from the drawback that the profile of each inoperative DCS may not always be accurate. In practice, the profile for each DCS is obtained by periodically reconnoitering that DCS. Depending on the traffic it carries and its location, a DCS may only be reconnoitered no more often than every six months. Between such six-month intervals, a telecommunications network service provider will likely re-provision a DCS to alter its cross-connections to add, remove or modify service. Hence, there is a significant likelihood that the stored profile for a given DCS will not include such recent provisioning information. Hence, that restoration of a DCS using its stored profile often did not result in a complete restoration of all service. Moreover, manual extraction of the circuit mappings and subsequent translation into a format appropriate for a particular DCS often took significant time. Thus, not only were the restoration mappings potentially inaccurate, but such mappings took significant time to acquire.
Thus, there is need for a technique for achieving network restoration that overcomes the disadvantages of the prior art.
Briefly, in accordance with the invention, a method is provided for restoring a network element, such as a Digital Cross-connect system (DCS) in case such element loses its circuit mappings. In accordance with the invention, updates from network elements indicative of a change in each network element""s configuration, i.e., a change in the element cross-connections, are received at a local controller network. A restoration map is then established for each network element in a language corresponding to that element by a DCS Operation Support System (DCS-OSS) for storage in a database associated with the DCS-OSS. In case of the need to restore a selected element, the database is queried to obtain the map for the selected element. Thereafter, the map for the selected network element is appropriately directed (communicated) to effect restoration. In some instances, the map is directed to the selected element itself. In other instances, the restoration map is directed to an intermediate network element (e.g., a DCS in a laboratory environment) having the same configuration. From the intermediate element, a technician can generate a restoration map on a storage medium, such as a floppy disk, for example, for subsequent transfer to the selected element. Alternatively, the map may be directed to a target network element on which the service is restored in place of the selected element. Upon receipt of the restoration map, restoration is accomplished via the target element.